The present invention relates to a camera unit for monitoring a spatial region. More particularly, the invention relates to a camera unit for monitoring a spatial region in front of a moving machine part of a press brake or a similar type of machine having a first machine part moving towards a second machine part.
Moreover, the invention relates to an apparatus for safeguarding such a machine. Such an apparatus is sometimes referred to in the art as a concurrently moving or mobile safety device.
EP 0 597 934 B1 discloses a mechanical construction for an electronic camera that is said to afford a large number of different application options since component carriers for electronic assemblies can be optionally supplemented. The known camera has a lens having a lens body, which can be screwed into a matching threaded hole on a front plate of the camera housing. For its part, the front plate is screwed to a housing body, in which various component carriers are accommodated. The camera has an image sensor, which is plugged onto a holding plate accommodated in the camera housing. The holding plate is connected via plug connections to a component carrier that receives further electronic components. The known camera enables relatively simple assembly by plugging together and screwing together the individual camera components. What is disadvantageous about the known camera system, however, is that the image sensor and the lens cannot be individually oriented or aligned with respect to one another. The orientation of the lens and of the image sensor with respect to one another is fixedly predefined by the dimensions and the manufacturing tolerances of the individual components.
A construction that is mechanically defined in this way may be sufficient or even desirable for many applications. For a camera unit intended to serve as part of a safety-related control unit for safeguarding a machine or installation, however, it is desirable to orient the image sensor and the imaging optical unit including a lens etc. individually with respect to one another in order to be able to evaluate individual pixels or pixel regions of the image sensor in a specific manner, for example. On the other hand, the mechanical construction of a camera unit intended to be used as part of a concurrently moving safety device on a press brake must be very robust and, in particular, withstand severe shocks and vibrations. The alignment of image sensor and lens must not be lost despite severe shocks and vibrations that might occur in some instances. Of course, it is also desirable to assemble the camera unit and align the image sensor simply and rapidly in order to keep down production costs.